Study Of Water Use And Quality Watermelon Under Regulated Deficit Irrigation Condition In Arid-Hungriness Oasis Area

The paper studied water use and quality of watermelon under Regulated Deficit Irrigation condition in arid-hungriness oasis area, Gansu province. The experiment was conducted in the farm of the center of agriculture and technology in Minqin county. The average irrigation of the area was used for the deficit of the experiment. According to growth characteristic of watermelon, four growth stages was use for deficit stages of the experiment, as follows: seeding-flowering, flowering-fruit bearing, fruit bearing-swelling and swelling-maturing. There were nine treatments and two repetitions in 2005 and three repetition in 2006. The experiment was started form the 26th April to 15th August in 2005,112 days. In 2006 was started from the 28th April to 15th August, 110 days. The research fruit was as follows:1) Different water deficit in different growth stages will reduce the growth of main caudex, leaves, area of leaf, rhizome, flowers and roots. Watering again after moderate water deficit, the compensatory effect was occurred in caudexes, roots, and leaves flowers and so on. It can decrease the difference between different treatments.2) In the stage of seeding-flowering, the deficit of water will reduce the diurnal change of leaf conductance, transpiration and photosynthesis in the same time. In the stages of fruit to swelling, the deficit of water will reduce the transpiration of leaf.3)ET would become bigger if irrigation became more;The biggest ET occurred in treatment 9:416.36mm in 2005 and 433.37mm in 2006,The lowest ET occurred in treatment 5: 344.65mm in 2005 and 357.69mm in 2006;The biggest WUEET and WUEI occurred in treatment 6;The crop coefficient made cleat that the key stage of consuming water of watermelon was the stage of fruit bearing to swelling.4) The highest yield occurred in treatment 5 which conducted moderate water deficit in the stage of fruit bearing to swilling: 40.5t/hm2 in 2005 and 38.1t/hm2 in 2006; Different water deficit in different growth stages will increase the concentration of Vc and SSC.